Gas turbine engines, such as turbofan gas turbine engines, may be used to power various types of vehicles and systems, such as aircraft. Typically, these engines include turbines that rotate at a high speed when blades (or airfoils) extending therefrom are impinged by high-energy compressed air. Consequently, the blades are required to be able to transfer a significant amount of heat in order to maintain a suitable operating temperature.
For purposes of heat transfer, a blade cooling scheme is typically incorporated into the turbines. The blade cooling scheme is included to maintain the blade temperatures within acceptable limits. In some cases, the blade cooling scheme directs cooling air through an internal cooling circuit formed in the blade. The internal cooling circuit consists of a series of connected, serpentine cooling passages, which may incorporate raised or depressed structures therein. The serpentine cooling passages increase the cooling effectiveness by extending the length of the air flow path. In this regard, the blade may have multiple internal walls that form intricate passages through which the cooling air flows to feed the serpentine cooling passages.
Ribbed channels are widely used in the serpentine cooling passages of turbine blades. In this method of cooling, relatively cold air is forced through a series of passages with ribs and heat is extracted from the turbine blades. The cooling air is usually bled from high pressure compressor stages and reduces the core mass flow rates and thus a penalty on engine efficiency. Efficient methods of cooling with high heat transfer rates are required to minimize the coolant requirement.
As the desire for increased engine efficiency continues to rise, engine components are increasingly being subjected to higher and higher operating temperatures. However, current engine components, such as turbine blades, may not adequately transfer enough heat for operation at such higher operating temperatures. In particular, current turbine blades may be able to transfer enough heat to maintain a suitable operating temperature.
Accordingly, it is desirable to have an improved blade that may operate with improved durability when exposed to high engine operating temperatures. In addition, it is desirable to have an improved blade that is relatively simple and inexpensive to implement. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.